1. Field of the Invention
The present invention relates to an image shake correction apparatus, and to optical equipment and imaging devices provided therewith.
2. Description of the Related Art
Image shake correction apparatuses have been proposed which are incorporated into imaging devices such as digital cameras for purposes of correcting image shake due to device shake of an imaging device. An image shake correction apparatus has, for example, a function which rotates as necessary a movable member that holds a lens or an imaging element in a lateral direction (yaw direction) and a vertical direction (pitch direction) viewed from an optical axis direction, and which conducts drive control in a plane that is perpendicular to the optical axis.
Now, an image shake correction apparatus has been proposed wherein the movable member is directed by a guide shaft and a guide groove provided in the movable member and a fixed member, and the directions in which the movable member can move are the two directions of rotational movement centered on the guide shaft and translational movement along the guide groove (see Japanese Patent Laid-Open No. H10-10597 and Japanese Patent Laid-Open No. 2010-152020).
The image shake correction apparatus disclosed in Japanese Patent Laid-Open No. H10-10597 uses drive units in which motors drive feed screws in the yaw direction and the pitch direction. The site where the yaw-direction drive unit operates is an elongate hole that extends in the pitch direction, and the site where the pitch-direction drive unit operates is an elongate hole that extends in the yaw direction. Consequently, the movements of the respective drive units are independently conveyed to the movable member. However, with this image shake correction apparatus, depending on the position of the movable member, for example, a locus of working points of the feed screw in the yaw direction when the pitch-direction motor is driven is not linear, but is a planar locus that changes according to the positions of the respective motors. Accordingly, in the case where a drive unit such as a feed screw that is only driven in one direction is used, when the movable member is moved beyond a range where the locus of working points can resemble a straight line, twisting occurs at the site where the feeding screw is operated. Therefore, it is difficult to increase the movable range of the movable member.
On the other hand, the image shake correction apparatus disclosed in Japanese Patent Laid-Open No. 2010-152020 uses a flat voice coil motor (a motor using a coil wherein the central axis of winding is perpendicular to the mobile surface). With this motor, as drive force can be exerted even when there is two-dimensional movement of the coil relative to the magnet, twisting does not occur even if the amount of mobility is increased, and the lens holding member can be planarly driven. However, with this image shake correction apparatus, when one of the voice coil motors is driven, the relative position of the coil to the magnet changes in the other voice coil motor, reducing the area of opposition, thereby reducing motor efficiency, and inhibiting increases in the amount of mobility of the movable member.